The present invention relates in part to a method for making organobis(thioetherimide)s having the formula, ##STR1## where R is a C.sub.(2-20) divalent organo radical, and R.sup.1 is a C.sub.(1-14) monovalent organo radical. The organo bis(thioetherimide)s of formula (1) can be hydrolyzed to the corresponding anhydrides thereafter copolymerized with aromatic diamines to make polyimides.
Prior to the present invention, as shown by F. J. Williams, U.S. Pat. No. 3,933,862, and U.S. Pat. No. 3,933,749, aromatic bisimides and dianhydrides were made by displacing nitro radicals on nitrophthalimides with bisthiophenols. Bis-thiophenols, however, are not readily accessible, since they have to be synthesized in a multistep manner.
The present invention is based on the discovery that N-substituted phthalimidothiolate can react with alkylene dihalides, or activated dihalo aromatic compounds to provide the organobis(thioetherimide)s of formula (1), as shown by the following equation, ##STR2## where R and R.sup.1 are as previously defined, and X is a halogen radical.